Instrument for checking the rate of time-piece movements



Dec. 16, 1958 F. MART] ETAL 2,864,661

INSTRUMENT FOR CHECKING THE RATE OF TIME-PIECE MOVEMENTS Filed Nov. 29, 1954 I 3 Sheets-Sheet 1 INVENTORS FRITZ MARTI GEORGES BRAUNSCHWEIG JEAN SCHAAD BY W s ATTORNEYS Dec. 16, 1958 F. MART] ET AL 2,864,661

INSTRUMENT FOR CHECKING THE RATE OF TIME-PIECE MOVEMENTS Filed Nov. 29, 1954 3 Sheets-Sheet 2 GEORGES BRAUNSGHWEIG J EAN SCHAAD BY {M ATTORNEYS Dec. 16, 1958 F. MARTI ET AL 2,864,661

INSTRUMENT FOR CHECKING THE RATE OF TIMEPIECE MOVEMENTS Filed Nov. 29, 1954 3 Sheets-Sheet 3 INVENTORS FRITZ MARTI GEORGES BRAUNSGWEIG JEAN SGHAAD I BY W W ATTORNEYS United States Patent INSTRUMENT FOR CHECKING THE RATE OF TIME-PIECE MOVEMENTS Fritz Marti, Georges Braunschweig, and Jean Schaad, La Chaux-de-Fonds, Switzerland Application November 29, 1954, Serial No. 471,852 Claims priority, application Switzerland February 26, 1954 3 Claims. (Cl. 346-79) The object of the present invention is an instrument for checking the rate of time-piece movements, comprising a synchron motor serving as a time standard and driving a rotary member provided with protruding ribs, an electromagnet energizable by the amplified tick-tocks of a timepiece to be tested, and a hammer controlled by the said electromagnet and co-operating with an inking device, to print the successive points of intersection between the ribs and the hammer on a recording band.

This machine is characterised according to the invention, in that the rotary member has the shape of an inverted bell mounted on the shaft of the synchron motor and surrounding the latter at least partially, the rim 'of the bell-shaped cage being formed with the protruding ribs and the recording mechanism being driven by the shaft of the motor through a gear-train located inside the said cage.

The synchron motor may be advantageously provided with an automatic starting device for the rotor.

The attached drawing shows, as an example, one form of execution ofthe machine forming the object of the invention, the elements necessary for its comprehension being shown only.

Fig. 1 shows a section along line II of Fig. 2.

Fig. 2 shows a partial plan-view, with some elements being represented in section.

Fig. 3 shows a side elevational view of the structure illustrated in Fig. 1 with several elements being shown in section.

Fig. 4 shows an elevation of the starting device for the rotor, some elements being represented in section.

Fig. 5 shows a plan-view of the same device, the mounting-plate of the machine having been omitted in part.

With reference to the drawing, the machine comprises, underneath the mounting-plate 1, a synchron motor (indicated diagrammatically by its stator 2 and its rotor 3) with its rotating shaft 4. On this shaft 4 is mounted with a certain angular backlash a cage 5, the spokes 5a of which extending from a hub to a circular rim 5b have the shape of an inverted bell and envelop the stator 2. The rim 5b, turning in a circular groove 6 provided in the lower face of the mounting plate 1, carries on its upper face and at regular intervals from each other a number of wedge-shaped projections or ribs 7, which are intended to cooperate across an opening in the mounting plate 1 with a hammer to print by means of an inkingdevice the successive points of intersection of the said ribs with the hammer on a recording band.

The recording band is drawn perpendicularly to the shaft 4 of the synchron motor by a drum 8 fastened on the hub of a worm 9, the horizontal shaft 10 of which is supported in bearings provided in the legs of a U-shaped support 11 fastened underneath the mounting-plate 1. The worm 9 meshes with a pinion 12 pivoting on a vertical stud 13 screwed in the mounting plate 1. The pinion 12 is fixed to a gear-wheel 14 meshing in turn directly with a pinion 15 cut in the upper end of the motor shaft 4.

The recording mechanism (see Fig. 5), comprising an inking ribbon 102 with its reversing mechanism 103, the hammer 100, the electromagnet 104 and a stretching pulley forthe recording band or inking ribbon, is mounted as a unit between two vertical side-plates 16, 17 hinged to the mounting plate 1 by a hinge 106. The inking mechanism is driven by a gear-train, the first unit of which is a pinion 18 fastened to one end of the horizontal shaft 10.

It will be noted that the starting point of the drive of the recording mechanism is situated at the upper end of the synchron motor shaft and that the whole of the geartrain of this drive is located inside the cage 5 which carries on its rim 5b the ribs 7, which are to co-operate with the hammer mounted underneath the mounting plate 1, to trace the beat-diagram of the time-piece to be tested. This arrangement permits of simplifying the construction of the driving mechanism and to reduce its dimensions and as a consequence to reduce also the volume of the entire machine.

A roll 24 provided with a rubber-sleeve 25 is fastened above the cage 5 to the shaft 4 of the rotor 3. Underneath the mounting plate 1 is fixed a startingand braking device for the rotor, acting by friction upon the roll 24, 25. This device, shown on Figs. 3 and 4, comprises a sector-shape lever 27, the rim 27a of which is intended to co-operate with the roll 24, 25. The lever 27 which is fixed by two screws 29 to the lever-extension 28, is pivoted by the hub 28a thereof on the lower end of a stud 3i screwed into a lug 1a of the mounting plate 1. On

this same stud 30 is pivoted a lever 31, the arm 31a of -plate 1 are pivoted one above the other two identical earns 38, 39 provided each with a nose 38a, 39a and carrying on its respective lower faces a pin 40, 41. These two pins are coupled mechanically by a helical spring 42, the purpose of which is to maintain the two cams in their reciprocal working positions. Opposite the noses 38a, 39a, the cams 38, 39 are provided with notches 38b, 39b and other noses 38c, 39c. Co-operating with the noses, 38c, 39c of the other cam, these notches are to engage and lock, each in turn, with a pin 43 fixed to the upper face of the sector-lever 27, 28. A stop-bolt 44 fastened to the extension 28 of the sector-lever 27 by means of a screw 45 is intended to engage with the cams 38, 39 at the end of their stroke.

The bolt 36, to which is attached an end of the torsion spring 35, is screwed into a slot 46 of the extension 28 of the sector-lever 27, thus permitting to adjust the reciprocal positions of the sector-lever 27, 28 and the lever 31.

In the position in which the various elements are shown in Fig. 4 by dotted lines, the motor is at standstill. By means of its rim 27a, the sector 27 bears against the rubber-sleeve 25 of the roll 24 fixed to the rotor 3, thus preventing it from turning. If the control-button 32 is shifted in the direction of the arrow F the lever 31 pivots in a counter-clockwise manner, thus tensioning the torsion spring 35. The release-pin 33 will come to bear against the nose 39a of the cam 39, causing the latter to turn in a clockwise direction. By means of the spring 42, the cam 39 will then cause the cam 38 to turn also clockwise and, at the end of its stroke, to suddenly release the pin 43 fixed to the sector-lever 27, 28. This latter will as a consequence be suddenly displaced counter-clockwise by the spring 35 and its rim 27a being suddenly shifted in the direction of the arrow F will engage with the roll 24, 25 and will thus start same as well as the rotor 3 to a speed at or near the synchronous speed of the motor.

At the end of its stroke, the pin 43 may be used to close a contact, for example a contact inserted in the motor supply-circuit. Thus, by shifting the control-button 32 in the direction of the arrow F the rotor is started and the feeding circuit of the motor is closed at the same time.

Inversely, the elements of the starting device being in the position as shown in full lines in Fig. 4 (running position of the motor), the control button 32 being shifted in the direction of the arrow F will cause the lever 31 to turn in a clockwise manner. The latter will tighten the spring 35 in the opposite direction. The pin 33 will come to bear against the nose 38a of the cam 38, thus causing the latter to turn counter-clockwise. By means of the spring 42, the cam 38 will cause the cam 39 to turn in the same direction. Cam 39 will, at the end of its stroke, liberate the pin 43 which in turn will provoke the sudden angular displacement of the sector 27, 28 in a clockwise direction, thus braking the roll 24, 25 and at the same time opening the contact inserted in the motor-circuit.

The functioning of the device is therefore reversible, viz. starting or braking of the synchron motor and at the same time closing or opening of the circuit of the said motor.

It is evident that the device could of course be used to close or open another contact, inserted in an auxiliary circuit.

What we claim is:

1. In an instrument for checking the rate of time-piece movements, comprising a top plate, a synchronous motor serving as a time standard, a rotary member driven by said motor, marking ribs provided on said rotary member, which rotary member is mounted below said plate, an

electromagnet energizable by the amplified tick-tocks of a time-piece to be tested, and a hammer controlled by said electromagnet and cooperating with an inking device to print, on a recording band, the successive points of intersection of the ribs with the hammer, the improvement in said instrument which consists of a gear train driven by the shaft of said synchronous motor and driving said recording band, said rotary member being a cage in the shape of an inverted bell, said cage being mounted on said motor shaft and substantially surrounding said synchronous motor as well as said gear-train, said ribs being provided on the rim of said bell-shaped cage.

2. In an instrument of the character described, the improvement as claimed in claim 1, wherein the vertical shaft of the synchron motor drives by its upper end a gear turning about a vertical stud and rigidly connected to a pinion meshing with a worm secured on a horizontal shaft carrying the driving drum of the recording band.

3. In an instrument of the character described, the improvement as claimed in claim 1, wherein the inking device comprises an inking ribbon driven by a gear-train the first element of which is a pinion secured on a horizontal shaft carrying the driving drum of the recording band, said horizontal shaft being in turn driven through a gear-train by the upper end of the motor shaft.

References (Iited in the file of this patent UNITED STATES PATENTS 523,362 McDonald July 24, 1894 1,123,279 Hamilton Jan. 5, 1915 1,386,120 Kuenneth Aug. 2, 1921 1,568,704 Warren Jan. 5, 1926 1,792,814 Capps Feb. 17, 1931 2,259,309 Hibbard Oct. 14, 1941 2,330,416 Gibbs Sept. 28, 1943 2,421,781 Gibbs June 10, 1947 2,478,346 Van Doorn Aug. 9, 1949 2,532,631 Loria et al. Dec. 5, 1950 

